I can't tell you how many times I've accedentally plowed into my escort while leaving port.
I also once was getting attacked by a DD in a storm. After a while, I heard nothing in my hydrophone and assumed he was gone. I snuck up to periscope depth and went to raise the periscope. It went halfway up when I heard a "KLUNK!" I angle the periscope up and see the bottom of the destroyer sitting right above me pointed the exact same direction as my boat. Just sitting there. Suddeny it sped up and I saw all these drums drop into the water. One bounced off the lens of my periscope and exploded sending me and my crew to a watery grave.